The number of echoes combined into a single image or image set in multiple echo imaging sequences or echo-train techniques such as rapid acquisition with relaxation enhancement (RARE), fast-spin echo (FSE), and turbo spin-echo (TSE). In RARE imaging, the ETL typically equals the acceleration factor.
As for tooth pain, it is caused by a reaction of the nerves inside a tooth's pulp chamber with the severity dependent upon the type and degree of the stimulus. What follows are some examples of symptoms you may be feeling and their possible causes.
1 Cold sores later crust over with a scab and are usually associated with tingling, tenderness, or burning before the actual sores appear. 2  Mouth irritation. 3  The irritation can be caused by: 4  Biting your cheek, tongue, or lip. 5  Wearing braces or another type of dental apparatus, or having a sharp, broken tooth.